Near-Zero Power Integrated Microsystems for the IOT

State-of-the-art sensors are not "smart" enough to identify targets of interest. They consume power continuously to monitor the environment even when there is no relevant data to be detected. This paper presents a new class of zero-power microsystems that fundamentally break the paradigm, remaining dormant, with zero-power consumption, until awakened by a specific physical signature associated with an event of interest. In particular, we demonstrate infrared (IR) digitizing sensors that consist of plasmonically enhanced micromechanical photoswitches (PMPs) that selectively harvest the impinging electromagnetic energy in design-defined spectral bands of interest and use it to create mechanically a conducting channel between two electrical contacts, without the need for any additional power source. Such a passive IR digitizer is capable of producing a wake-up bit when exposed to a specific IR spectral signature associated to a target of interest while rejecting background interference. Here we show the device characterization, system level integration with commercial off-the-shelf electronics, and three application examples of the zero-power IR sensors (plant water content monitoring, flame detection and human presence sensing). The capability of these zero-power sensors of consuming power only when useful information is present results in a nearly unlimited duration of operation, with a groundbreaking impact on the proliferation of the IoT.